Synthesis and Proton Conductivity of Partially Sulfonated Poly([vinylidene difluoride-co-hexafluoropropylene]-b-styrene) Block Copolymers

Abstract

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Nanostructure, Morphology, and Properties of Fluorous Copolymers Bearing Ionic Grafts

“…This observation agrees with the experimental data for P(VDF-co-HFP)-b-SPS diblock copolymer membranes where the activation energy is reported to fall from 25.7 to 17.1 kJ/mol as IEC increases from 0.72 to 1.18 mmol/g. 56 As shown previously in the TEM images, membranes with lower IEC form smaller, more isolated ionic clusters; thus, the energy barriers for both water swelling and proton motion are greater.…”

Structural Study of Proton-Conducting Fluorous Block Copolymer Membranes

“…Measurements performed on both series show that the conductivities are comparable for similar IEC. Results from Shi and Holdcroft 23,25 are reproduced in Figure 16; the samples studied by SANS are indicated on the figure by large circles (series 2) or squares (series 1). The conductivity of membranes from series 1 appears to level off and even decrease at high IEC.…”

“…Tangential proton conductivity at room temperature and at 100% RH was measured by ac impedance spectroscopy with a HP 8753A network analyzer, using a frequency range of 300 kHz to 1 GHz and a gold-plated coaxial probe 23 and using Nafion as a standard sample. The protocols used to measure and calculate the number of water molecules per ionic site, λ value, and the ion exchange capacity, IEC, of the whole molecule, are presented in the refs [23][24][25]. The fluorous block number-average molecular weight, M n , was measured using a gel permeation chromatograph, GPC, using three µ-Styragel columns, a Waters 510 HPLC, polystyrene standards, THF eluant, and a Waters 410 differential refractometer.…”

“…This observation has been attributed to the decrease in proton concentration observed in these samples when highly hy- drated. 23,25 Unfortunately, the membrane with the highest conductivity, which was from series 2, was not studied by SANS because it swelled to a water content of 61% when hydrated and could not be handled easily.…”

Transport and Electro‐Optical Properties in Polymeric Self‐Assembled Systems

“…Sulfonated poly(aryl ether ketone) copolymers based on 4,4'-(hexafluoroisopropylidene)diphenol, 1,3-bis(4-fluorobenzoyl)benzene and disulfonated difluorobenzophenone have good thermal and oxidative stability [211]. Amphiphilic block copolymers comprising sulfonated poly(vinylidene difluoride-co-hexafluoropropylene)-b-polystyrene were synthesized having moderately low polydispersity index [212,213]. Transmission electron microscopy studies suggested interconnected networks of ion channels, each 8-15 nm wide and the conductivity was of the same order as that of Nafion.…”